A standard hypodermic syringe comprises a bottle having a neck normally fitted with a plug that in turn is formed with an axially throughgoing passage that may be blocked by a thin frangible membrane. A stiffening sleeve formed of a synthetic resin somewhat stiffer than that of the plug fits over the neck and plug and forms a forwardly projecting collar to which is fitted the hub of the needle cannula when the device is used. A stopper can be fitted in and/or over the collar to maintain sterility.
With such an arrangement, unless it is provided in a sealed package, it is impossible to know if the interior of the bottle is sterile, whether or not it already contains some injectable medication. Even if a package is provided, once it is opened it is impossible to tell if the interior of the bottle remains sterile.